GP76851 Mixer Cap and Pressure Balancing Unit Parts Cartridge Compatible with Kohler, Replacement for Rite-Temp and 1/2 Shower Valve

Cartridges by GreatUs. Details:replace for the model#GP500520 and GP77759 for 1/2″ Shower Valve,AND Controls pressure and regulates temperature to ensure a gracious shower experience. for leakage 1. O-ring is the key, must be replaced, and add lubricant, then firmly placed in the correct position. 2. Do not rotate the Cartridge, just put it in, otherwise the O-ring will shift and cause leakage. 3. Tighten the screws to fix the cap and the Cartridge, or will also cause leakage.